Knowledge

When it comes to deciding between using 6061 aluminum alloy or 7075 aluminum alloy for a project, understanding their differences and applications goes a long way. For most general purposes, both alloys can get the job done. But the differences in composition, mechanical properties and cost can help you choose what fits your needs best.

Like most aluminum alloys, both exhibit good corrosion resistance, and high strength-to-weight ratios.

CHEMICAL DIFFERENCES

The chemical differences between 6061 and 7075 aren't readily visible. Both contain magnesium, silicon, copper, iron, zinc, titanium, manganese and chromium. But the difference is how much is contained in each.

Specifically, 6061 aluminum contains less zinc than 7075. Meaning that while 6061 alloys provide superior welding abilities and workability, it doesn't boast the same high strength and stress resistance as 7075.

APPLICATIONS FOR 6061 VS 7075

6061 Aluminum

6061 is highly versatile and can be used for almost any structural component. Commercial and personal vehicles utilize 6061 for frames and running boards. Infrastructure uses it in mass transit and subway platforms, steps, flooring, walkways and cover plates. Consumer products such as bicycle frames and components, SCUBA tanks, fishing reels and small utility boats all benefit from the increased weldable nature and its ability to undergo hot forging.

Use 6061 when:

You need to do a lot of machining on the part

You need to do a lot of welding on the project

Cost is a main factor

7075 Aluminum

7075 is notable for its high strength-to-weight ratio and improved strength over 6061. Because of this, 7075 is largely used in aerospace, marine and transportation industries. Any industry where high strength and light weight properties are critical, this alloy is preferred. High-end bicycle components, molds for the plastics and tool industries, airframes, and even military-grade rifle receivers all heavily utilize 7075.

Use 7075 when:

High strength and low weight are crucial

The part will be exposed to a lot of heat

The part will be exposed to a lot of friction and needs to be hard

Cost is less of a concern

MECHANICAL PROPERTIES OF 6061 VS 7075

Looking for more concrete numbers? We have those here, both in the T651 temper.

General Mechanical Properties of 6061 (T651)

Tensile Strength – 45,000 psi

Yield Point – 40,000 psi

Brinell Hardness – 95

Elongation at Break – 12%

Shear Strength – 31,000 psi

Thermal Conductivity – 170 W/m-K

Strength to Weight Ratio: 115 kN-m/kg

General Mechanical Properties of 7075 (T651)

Tensile Strength – 83,000 psi

Yield Point – 74,000 psi

Brinell Hardness – 150

Elongation at Break – 10%

Shear Strength – 48,000 psi

Thermal Conductivity – 130 W/m-K

Strength to Weight Ratio: 196 kN-m/kg

Fuller mechanical and chemical information for both alloys, including different tempers, is available in their respective.